Wheel aligner



June 19, 1945'. H. G. HOLMES 2,378,631

' WHEEL AL'IGNER Filed Oct. 19, 1942 I 4 Sheets-Sheet 1 l WAC/V70?" amy? 4 #014117 Jun 19, 1945.

H. G. HOLMES 2,378,631

WHEEL ALIQNER Filed Oct. 19, 1942 4 Shets-Sheet 2 I H. G. HOLMES WHEELALIGNER June 19, 1945.

4 Sheets-Sheet 3 Filed Oct. 19, 1942 June 19, 1945. H. G. HOLMES 8,

WHEEL ALIGNER Filed Oct. 19, 1942 4 sheets-sheet 4 It is an object ofthe present invention Patented June 19, 1945 p.125; 1,;

UNITED? STATES rnrsN-T 'orF-lece I wnrzii zfjlvnn it Herbert G; Holmes,Lansing, Mich, assignor. 'to

Food Machinery Corporation, San.

Jose, Calif.,

a corporation of'Del'awarefl I Application October-19, 1942, seria1- No.462,476

8 Claims. (01, 33-203) This, invention. relates; to; the art: oftmeasuring the alignment characteristics of. a pairofidirigible wheels ofa vehicle. and particularly to an apparatus. adapted. fonchecking thecamber, caster,

king pininclination,toe-inand toe-out ofteach of such a dirigible pairof wheels,

Apparatus intcommon, use for this general purpose is shownin. U. S.Letters; Patent. to J; W;

2,108,383, and Herbert awheel to measure each of the alignment char'-.

acteristics mentioned. a todecreaseJthe-number oftimes the base of thedevice acteristic as aforesaid.

A. specific instance of difficulty met within the prior 'art practiceis' in the measurement of caster which involves the reading of. anglesat which a,

bodiment; of the'invention. as when applied: to 'a wheel in. themeasuring. of camber.-

Fig; 2 is, across section. showing the device-in side elevation andtaken on the line 22'of Fig. 1.

Fig. 3 is a plan view of thedevice as when applied to awheel inthemeasuringof caster.

Fig; 4 is an: enlarged fragmentary verticalview taken on. the .line 44.of Fig. 3. with the parts positioned as shown in Fig. 2. Fig. 5 isan.enlarged fragrnentary, horizontal viewtaken'on the line 5+5 of Fig;4.

Fig. 6. is an enlarged detail sectionalview'taken on line a t-of Fig. 2and illustrating thedouble camberscaleplate.

Fig.7 is a fragmentary vertical sectional view illustrating a modified;form of the invention.

wheelbeing'tested isdisposedin-both vertical and horizontal planes. I

It is a further objectof the present inventionto provide an apparatuswhich will?- accomplish this dual measurement with a greater degree ofaccurac and. with lessv manipulation and checking than-are required withdevices. of? the prior art.

, When installing wheel aligning apparatus it is difficult to get the.base exactly level; Also the foundation provided occasionally settlesafter installation. These conditions throw'the-apparatus out of plumband introduce inaccuracies into the wheel aligning tests.

It is another object of the invention to provide such an apparatuswhich-has within itselfmeans for compensating for the supporting'basenot be} ing level.

A further object of theinventi'on is tofprovide.

such'an apparatusby which camber can be quick- 1y measured either fromthe tire or' from the rim.

with a relatively small amount. of, adjustment of theapparatus;

The. manner ot. accomplishing, the, foregoing;

objects. as. well as. other objects J and. advantages will'be.mademanifest. in. the; following. descrip- Before describing theillustrated embodiment of the invention in detail itis desiredfto defineeach of the; alignment characteristicsabove referred to.

Camber is they angle that afrontawheel is tilted outwardly at the topfrom vertical;

Casteris the angle which a king pin is tilted backward at the top fromvertical.

' King pin, inclination is" the angle which'. a. king pin is tiltedinwardly at the topfrom vertical.

- Toe-in is the angle which. a-horizontal diameter of a wheel isinclined forwardly towards the longitudinalaxis of thevehicle. I"Toe-out, orsteering geometry, relatesftothe m'echanicsof keeping thefront wheels aligned with their respective directions of movement as thevehicle turns to theright orleft. c

For an explanation of'the practical significance of the characteristicsabove defined, reference is had tothe patents of the prior art;

The apparatus ID of mypresent invention is I adapted for measuring eachof the aforesaid alignposed on its upper surface at right angles totheand'rear wheels on one side. of the vehicle being measured. Each ofthese. units includes a base I2, providing a runway l3, onto which, saidtwo wheels of said vehicle are run, and a turntable M, provided on saidbase. on which the front wheel. it of said pair is brought to restasshown.

in Figsl and 2.

Opposite the turntable M, the. base.l2 has a lateral extension Hproviding a slideway l8 disrunway. l3; Slidably mounted on the slidewayI8 is a gauge body zll, movement of which along the slideway iscontrolled by, a lever 2| pivoted on the slideway I8 and connected tothe gauge body 28 by a link 22. Gauge body 28 includes a standard 23having a head 24 at its upper end and a bracket 25 extending inwardlytherefrom. The body 28 has a bolt 26 extending downwardly through a slot21 in the slideway I8 and having a spring 28 on said bolt which holdsthe head 29 thereof upwardly against the slideway on opposite sides ofsaid slide. This retains the gauge body 28 on the slideway I8 whileallowing this body to he slid along said slideway by manipulation of thelever 2 I.

The head 24 has a scale mounting bracket 35 and is provided with ahorizontal bore 36 and a stop limit screw 31 adapted to extend a limiteddistance into the bore 36 as shown in Fig. 4;

Mounted onthe bracket 35 is a scale plate 38 having arcuate scales 39and 48 fixed thereon, the graduations on each of which will be describedhereinafter.

The bracket 25 has a vertical opening 45, a vertical bore 46 and a Setscrew 41 penetrating to said bore. This bracket also has stop lugs 48extending upwardly from the bracket on opposite sides of the opening 45.

Extending inwardly from the opening 45 are guide ledges 49 which aremachined to provide parallel guide surfaces, the purpose of which willbe made clear hereinafter.

Extending into the bore 36 of the head 24 is a cylindrical shank 58 of abifurcated pivot bracket carrying a pivot pin 52. The shank 58 traps acoiled expansion spring 53 between it and the blind end of the bore 36and is held against rotation in said bore, with a limited degree oflengthwise movement therein, by the stop screw 31 extending downwardlyinto a groove 54 pro vided longitudinally in the upper surface of theshank 58. Extending upwardly from opposite forks of the pivot head 5|are plates 68 having arcuate upper edges concentric with the pin 52 andon which is fixed a scale plate 6|, this plate having caster scale 62and camber scale 63 mounted thereon. The precise nature of the indiciaon these scales will be indicated hereinafter. The caster scale 62 isslidably adjustable on the plate 6|.

Lying between the forks of the bifurcated bracket 5! and supported onthe pin 52 is a contact bar slide head 64 having stop shoulders 65 and66 which engage the bracket 5| to limit the rocking of the head 64 aboutthe pin 52. This head also has contact bar slide openings 61 and 68through which 9, contact bar 69 slides, this being yieldably retainedthereon by a spring detent I8 which continuously presses inwardlyagainst the bar 69. The bar 69 is preferably square and is dimensionedto neatly slide between the parallel guides 49 of the bracket 25.Secured to and extending upwardly from the pivot head 84 are indicatorarms TI and I2. Arm II has finger I4 overlying the caster scale 62. ArmI2 has fingers I5 and I6 overlying the camber scale 63 as shown in Figs.1, 2, 3 and 6.

Slidably provided on the upper and lower ends of the bar 69 are wheelcontact arms 11.

Fastened in the bore 46 of the bracket 25 by application of the setscrew 41 thereto is a vertia horizontal contact bar 88 is slidablymounted.

Each of the sleeves 86 is provided with a detent spring 89 which bearsagainst the bar 88 and thereby retains this bar in any given position inwhich it is placed in the sleeves 86. slidably mounted on the oppositeends of the bar 88 are wheel contacting arms 98.

Extending upwardly from each of the sleeves 86 is a boss 95, anindicator hand 98 being mounted on these bosses the extremity of whichsweeps over the scales 39 and 46.

The scale plate 63 has two scales, 9'! and 98. The first of these is formeasuring camber when end notches 99 of the arms 'I'l are engaging rimI88 of the wheel I6, as shown in dotted lines I85 in Fig. 2. Scale 98 isfor use in measuring camber when the arms 11 engage the tire H32 of thewheel I6, as shown in full lines in Fig. 2 and in Fig. 1.

The fingers I5 and 16 on the arm 12 are for use respectively with thescales 9'! and 98 as shown in Fig. 6. It will be noted that these scalesare alike, but for any angle indicated by the finger I5 on the scale 91the finger I6 indicates an angle on the scale 98 just three-eighths of adegree less. The necessity for this difference in angles indicated bythe two scales 6'! and 98 is because when measuring camber with the armsTI engaging the rim I88, as shown in dotted lines |8| in Fig. 2, the bar69 of the device is parallel with the rim I88, and thus with the wholerigid structure of the wheel itself including the bearings on which itis mounted. When measuring camber with the arm H in contact with thetire I82, as shown in full lines in Fig. 2, the bar 68 is deflectedapproximately three-eighths of a de gree out of parallelism with the rimI88 by the bulge at the bottom of the tire I82.

Fig. 7 illustrates a modification N8 of the apparatus of my inventionwhich is substantially like the apparatus I8 excepting for the manner inwhich a bracket I25, (which takes the place of bracket 25), is mountedon a standard i215, (which takes the place of the standard 23). BracketI25 is separate from the standard E23 and includes a vertical plate I26,the lower end of which has a bolt I21 fixed therein which extendsthrough a relatively large hole I28 in the standard I23, so as to permita limited degree of adjustment of the lower end of the plate I26relative to the standard I23.

The upper end of the plate I26 has a stub shaft I38 which extendsthrough and is rotatable in a bore |3| provided in the standard I 23.The plate I26 has a bore I32 which is concentric with and extends intothe shaft I38, this bore receiving a shank I58 of a pivot bracket I 5|(which take the place of the corresponding parts 58 and 5| of theapparatus ID). The shank I58 is trapped in the bore I32 so as to confinea spring I53 therein by a set screw I54, the latter extending into anotch I 55 (which corresponds in function to the notch 54 in shank 58).The extending end of the stub shaft I38 has fixed thereon a fitting I68,on which is provided a scale plate |6| (which corresponds to the scaleplate 38 in the apparatus I8).

The principal advantage of the apparatus ||8 over the apparatus I8results from the fact that cal pivot pin 83, on which a contact barslide 7 in installing this apparatus the foundations therefor aresometimes not level, so that an error is thus introduced into thereadings accomplished by the device. One of these errors results fromthe plane which includes both the axis of the bar 69 and the axis of theshank 58 not being vertical in taking caster readings. the apparatus.I-I-lI this plane can be checked with a levelwand proper adjustmentmade by loosening up the bolt 1 2 I and shifting the lower end of *theplatetl26 to swing the bracket I .25 about the :axis ofthe stub shaft I.30. ..When the proper adjustment has been made the bolt IZ'I-is thentightened up to bind the lower end of the plate 126' rigidly tothestandard; I23; 1

' Operation As already indicated; camber may .be determinedby'theapparatus :IO in'either of two ways. One of these is shown in dottedlines IIH in Fig. Z'and the other is shown in full lines in Figs. 1 and2. The method'in most common use is that shown in full line and in whichthe arms I! are positioned on the bar 69 to lie opposite the upperandlower. portions of the tire IIlZ of the WheeIZIB and the handle 2| thenmanipulated to shift the unit I -I disposed adjacent this wheelinwardlyto bring the arms 9.0 and]? into contact with the tire of thewheel. Before this .is done the wheel of course is positioned, as nearlyas possible by the eye, with its horizontal diameter parallel withthefore and aft axis of ,the vehicle. When this parallelism has beenattained, this is indicated by the pointer 96 pointing to zero on theangle scale 39. p

'Sim 'taneouscon-tact of the arms TI and '98 with the tire of the wheelis made possible bythe provision .of the spring 53, which yields asindicated in' Fig. i, to permit the continuecl inward movement ofthe-body 2B of the device, to bring the arms. 90 into contact with thetire afterthe arms I! have already engaged the tire. It is thus seenthat all four armsmay be brought into contact with the tire with asingle easy movement of the unit body 20, merely by manipulation of thelever 2 I. The reason the arms Tl contact the tire I02 first is becauseof the bulge in the lower portion of this tire produced by a portion ofthe weight of the car being supported by'the tire.

v When the Wheel I6 has been adjusted'w-ith its horizontal diameterparallel with the fore and aft axis of the vehicle, as aforesaid, bybringing thea-rms I] and 9i! all into contact with the tire andadjusting the wheel until the pointer .96 reads at zero-on the scale 39,the camber of this wheel may be read in'degrees on -the scale-98. lf thefinger 16 were disposed at this time as shown'in Fig. 6, a camber ofone-halfya degree would be indicated.

The other Way of checking camber with the apparatus In is to go-throughexactly thesame steps of bringing the wheel t6 into parallelism with thecar, with the arms IT in dot-tedl-ine .positions .Ill I, and. thenreading the camber from the;

scale 81. It the-finger were dis-posed as shown in Fig. 6, a camber ofone-eighth-of a degreewould be indicated. 1 I Toascertain the caster, orrearward inclination of the vehicle, the lever 21 is retracted to movethe contact arms 90 and TI away from the wheel, the

angle of the latter adjusted and'the arms 90 and- Il again brought intocontact'with'the tire of the wheel until thehand 96 is brought to apoint on the gauge bodyZIl on the scale 39 as shown in Fig. 2,indicating that the wheel 16 has been-swung inwardly so that thediameter of this wheel ongaged by the arms 90 is disposed at an angle oftwenty degrees relative to the longitudinal axis of the vehicle.

When this angle hasbeen reached with the wheel I6. turned outwardly asshown in fulllines in Fig. 3, all four of the contact arms Hand 90 arein engagement with the tire of the wheel IS. The caster scale plate 62is now slid on the plate 6| until 0 thereon is opposite the pointer I4.The arms TI. and 9%] are now pulled away from contactlwith the wheel I6and (as shown in clotted so I from vertical, of the king pin of thewheel IB' (see Fig. 3) the unit I I is operated as follows: The carriage20 and associated parts are retracted from engagement with the tire ofthe wheel I6 by pulling on the lever 2| and the wheel I6 is then turnedoutward by the steering gear to an angle approximately twenty degreesrelativeto the fore and aft axis of the vehicle, as shown in full linesin Fig. 2. Then the carriage Zllis shifted inwardly and the bar 88 slidforwardly in the sleeves 8B and all four arms 7"! and 90 are broughtinto engagement with the tire of the wheel I6 as shown in Fig. 3. If thewheel was not swung to an angle of exactly twenty degrees with thelongitudinal axis lines in Fig. 3) this wheel is turned inward twentydegrees from parallelism with the axis of the vehicle being testedand-the unit I I again moved so as to bring all four arms TI and 90 intocontact with the-tire of the wheel I 6. The scale plate 62 is socalibrated that when this has been done, the pointer 74 will indicate onthe scale plate 62 the number of degrees of the caster of the wheel "5..I I

The mathematics by which caster is thus indicated is well known in theart and is so thoroughly explained in-the prior art patents on methodand apparatus for determination of caster that no detailed explanationof it is necessary here.

From an examination of my prior U. S. Patent No. 2,160,145, it will beseen that I can readily utilize one of the units I I to check thekingpin in clination of the wheel adjacent thereto. To do this, the arms I?shouldbe removed from the vertical bar 69. The upright scale plate 68 ofthe patent is then attached to the axle of said wheel and the contactingand positioning device 9|. of

" II points to zero on the'toe-in scale plate 40 thereof, and thenobserving the value on the scale plate 40' of the other unit II to whichthe hand spective front wheels I6 while one of these wheels is turned toa predetermined angle, measured on the scale plate 39 of the unitengaging this wheel, and then checking the angle indicated by the hand96 on the scale 39 of the other of said units.

As well known in the art these two angles for a car of a given wheelbase must have a certain relation according to a schedule furnished bythe manufacturer of the vehicle in order for both wheels to be inalignment with the path they are travelling along when the vehicle isturned.-

These angles must be such, of course, that the axes of all the wheels ofthe vehicle intersect at .said apparatus comprising a base;

a given point, this being the center about which the vehicle is turning.

What I claim is:

1. An apparatus for determining alignment characteristics of a frontwheel of an automobile, a carriage shiftable on said base toward andaway from said wheel; means mounted on a vertical pivot on said carriageand adapted when said carriage is moved toward said wheel to engageopposite points on said wheel substantially in a horizontal plane andmeasure the angle between said wheel in said horizontal plane and thefore and aft axis of said automobile; and a separate means pivotallymounted on said carriage on a horizontal axis and adapted to engage saidwheel in a vertical plane, when said carriage is shifted toward saidwheel, to measure the angle that said wheel is inclined from vertical ina plane normal to said axis.

2. An apparatus for determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising a base; a carriageshiftable on said base toward and away from said wheel; means mounted ona vertical pivot on said carriage and adapted when said carriage ismoved toward said wheel to engage opposite points on said wheelsubstantially in a horizontal plane and measure the horizontal anglebetween said wheel and a line normal to the direction in which saidcarriage is shiftable on said base; a separate means pivotally mountedon said carriage on a horizontal axis and adapted to engage said wheelin a vertical plane when said carriage is moved toward said Wheel tomeasure the angle that said wheel is inclined from vertical in a planeparallel with said direction; and means on said carriage adapting one ofthe aforesaid pivotally mounted means to yield with respect to saidcarriage when said carriage is moved towards said wheel.

3. An apparatus for determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising a base; a carriageshiftable on said base toward and away from said Wheel; means mounted ona vertical pivot on said carriage and adapted when said carriage ismoved toward said wheel to engage opposite points on said wheelsubstantially in a horizontal plane and measure the angle between saidwheel in a horizontal plane and a line normal to the direction in whichsaid carriage is shiftable on said base; a separate means pivotallymounted on said carriage on a horizontal axis and adapted to engage saidWheel in a vertical plane when said carriage is shifted toward saidwheel to measure the angle that said wheel is inclined from vertical ina plane parallel with said direction; and means on said carriageadapting the second recited of the aforesaid pivotally mounted means toyield with respect to said carriage and parallel with theaforesaiddirection' when said carriage is moved towards said wheels.

4. An apparatus for' determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising a base; a carriageshiftable on said base toward and away from said wheel; a horizontalwheel contacting bar; means for pivotally mounting said horizontal baron said carriage on a vertical axis; a vertical wheel contacting bar;means for pivotally mounting said vertical bar on said carriage on ahorizontal axis so that said vertical bar is in crossed relation withsaid horizontal bar and disposed to the rear thereof; and means on saidbars for contacting said wheel.

5. An apparatus for determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising a base; a carriageshiftable on said base toward and away from said wheel; a verticalmeasuring :bar; a horizontal measuring bar; means for separatelymounting said bars pivotally on said carriage on axes disposed at rightangles respectively with said bars; and means on said bars forcontacting said wheel.

6. An apparatus for determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising a base; a carriageshiftable on said base toward and away from said wheel; separatevertical and horizontal measuring bars; pivot heads in which said barsare respectively slidable; means for separately pivoting said pivotheads on said carriage on axes disposed at right angles respectively tosaid bars; and means on said bars for contacting said wheel.

'7. A combination as in claim 6 inwhich means is provided on saidcarriage for adapting one of said pivot heads to yield relative to theother pivot head when said carriage is moved toward said wheel toaccomplish an adjustment of said bars to said wheel.

. 8. An apparatus for determining alignment characteristics of a frontwheel of an automobile, said apparatus comprising: means optionallyshiftable in a vertical plane into parallelism with the tire of saidwheel or with the rim of said wheel; means for shifting the aforesaidmeans into either of said positions; and unitary angle indicating meansresponsive to the first aforesaid means to indicate in degrees thecamber of said wheel whenever said shiftable means is placed in eitherof the aforementioned positions, said angle indicating means comprisingduplicate scales and pointer means cooperating therewith, said pointermeans indicating on one of said scales the camber when said shiftablemeans is in parallelism with said tire, said pointer means indicating onthe other of said scales the camber when said shiftable means is inparallelism with said rim.

HERBERT G. HOLMES.

